Sailboat sails are hoisted by ropes called halyards. Conventionally, halyards were made of steel cable, for example, stainless steel, galvanized plow steel, or the like. These steel halyards generally were strong and had little or no stretch/strain over time. With the advent of high strength synthetic polymer fibers, such as Dyneema/Spectra, Vectran, or PBO (poly-p-phenylenebenzobisoxazole), halyards weighing about 25% of the weight of steel halyards with equal strength and stretch of steel halyards were developed. Today, these lightweight high strength ropes make up almost all of sailboat halyards.
Synthetic-based halyards, however, typically suffer from a disadvantage of “creep,” which is not found in steel halyards. Creep is the property of a material whereby it gradually strains and elongates under constant load. When a halyard slowly strains, the tension in the halyard decreases and sail trim is affected, such that the halyard must be regularly readjusted to maintain optimal sail trim. Especially on racing boats, consistent and accurate halyard tension is an important property. For non-racing boats, the slowly straining halyards can cause the sail to slowly develop wrinkles as tension eases, making for an unsightly sail, which can compromise the perceived beauty of a sailing pleasure yacht.
To combat this problem, halyard locks are regularly installed at the top of masts, so that creep can be avoided. Traditionally a halyard lock includes a hook that latches to a ball-like fitting on the halyard. This latch generally latches like a door latch. To unlock the lock, the sail is tensioned to relieve the load on the lock. Then, at deck level, a small diameter rope or “tripline” that runs either inside the mast or outside along the sail and attached to the latch is tensioned, releasing the sail. Since the masthead is typically too tall to be visible from the deck level, it is sometimes difficult to determine if the lock is locked, partially locked, or not locked at all. Often a crew member is sent aloft to confirm that the halyard is locked. Also, the use of multiple triplines can be problematic, for example, they can jam inside the mast, break, or make lock servicing difficult, and may require an additional crew member to operate.
It would therefore be desirable to provide a halyard lock that does not require a tripline. It would also be desirable to provide a halyard lock that allows a single crew member to raise and lock a halyard hoisting a sail and to unlock and lower the same.